In the past, a can pinhole inspection method (see PLT 1) and a can body pinhole inspection apparatus (see PLT 2) have been proposed. In such a can pinhole inspection method or inspection apparatus, when the conveyed can body passes through an inspection area including a predetermined position where a sensor is set, light is irradiated from plural sources of light, and the amount of light which leaks through an opening part of the can body is measured by the sensor to detect a pinhole in the can body. Specifically, while a can body passes through the inspection area, the light source is switched on, off, and on in state. It is judged that the can body is free of pinholes when all of the three measurement values among the three measurement values of the amounts of light by the sensor in the different states are the threshold value or less, it is judged that the can body has a pinhole when two of the measurement values exceed the threshold value, and it is judged that there is leakage of light or another abnormality in inspection when all of the three measurement values exceed the threshold value.
According to such a can body pinhole inspection method, it is judged that there is a pinhole in the can body only when two of the measurement values among the three measurement values exceed the threshold value, so it becomes possible to prevent mistaken detection of pinholes and perform more accurate inspection.